Phenazine-1,6-diol selectively inhibited non-small cell lung cancer via DR5-mediated apoptosis

Background Non-small cell lung cancer (NSCLC) is a lethal malignancy with limited treatment options. Natural products, particularly from marine sources, represent a promising avenue for discovering novel anticancer agents with high selectivity. Purpose This study investigated the antitumor efficacy and mechanism of action of phenazine-1,6-diol, a marine-derived compound, against NSCLC, with a focus on DR5-mediated apoptosis. Methods The cytotoxicity of phenazine-1,6-diol was assessed in NSCLC and normal lung cell lines. Apoptosis was evaluated via flow cytometry and Western blot analysis. The essential role of DR5 was confirmed in DR5-knockout H460 cells. The impact on PI3K/AKT/mTOR signaling was analyzed. In vivo antitumor activity and safety were evaluated in a Lewis lung carcinoma xenograft model. Results Phenazine-1,6-diol selectively inhibited the proliferation of NSCLC cells while sparing normal lung epithelial cells. It induced G2/M cell cycle arrest, suppressed colony formation, and triggered caspase-dependent apoptosis, as evidenced by increased cleavage of PARP and caspase-3/8, upregulation of Bax, and downregulation of Bcl-2. Mechanistically, phenazine-1,6-diol upregulated DR5 expression. Genetic ablation of DR5 profoundly attenuated its cytotoxicity and apoptotic effects. The compound also inhibited the PI3K/AKT/mTOR pathway. In mouse xenografts, phenazine-1,6-diol (20 and 30 mg/kg) significantly suppressed tumor growth, prolonged survival, and enhanced tumor apoptosis without causing systemic toxicity. Conclusion Phenazine-1,6-diol is a potent and selective anti-NSCLC agent that acts through two mechanisms: the induction of DR5-mediated apoptosis and the suppression of the PI3K/AKT/mTOR survival pathway. It presents a promising candidate for further development as a targeted therapy for NSCLC.